TM 1-1520-238-T-442447SYSTEM DESCRIPTION (cont)47M58-212AVENTBLEED AIR INPUTFIFTH STAGEMETERING VALVEAND FRONT FRAMETO SWIRL FRAMECAM PLATESWITCH34SOLENOIDSENSINGHMUACTUATORFigure 416.AntiIce and Start Bleed Valve Operation(4) Engine Start Subsystem.The starting system (fig. 417) uses air from the PAS and provides meansfor starting each engine. When the pilot power quadrant MASTER IGN switch is set to ON, 28 VDC is supplied totheENG START switch. Setting the ENG START switch momentarily to START initiates an automatic startsequence which sends a 28 VDC signal to the start relay in the engine start mode relay panel. The start relaysends the following signals:Regulator energize to the engine. The engine air pressure regulator opens, supplying PAS air tothe air turbine starter. The ECU/DECU sends a signal to the pilot power quadrant which lights theENG 1or ENG 2STARTindicators.Interlock valve to the ENCU shutoff valve. The valve closes to ensure all PAS air is available todrive the air turbine starter.Ignition enable to the engine ignition system. The ignition system supplies electrical ignition to theengine.Speed control switch to the engine speed cutout switch in the electrical power distribution box.This maintains the start sequence after the ENG START switch is released.When the engine starts it sends speed sensor to the engine speed cutout switch. The switchopens, ending the start sequence.